1998 Esso Longford gas explosion
Encyclopedia
The 1998 Esso Longford gas explosion was a catastrophic industrial accident which occurred at the Esso
natural gas plant
at Longford
in the Australia
n state of Victoria
's Gippsland
region. On 25 September 1998, an explosion
took place at the plant
, killing two workers and injuring eight. Gas
supplies to the state of Victoria were severely affected for two weeks.
and BHP. Esso was responsible for the operation of the plant. Esso was a wholly owned subsidiary of US based company Exxon, which has since merged with Mobil, becoming ExxonMobil
. BHP has since merged with UK based Billiton becoming BHP Billiton
.
Built in 1969, the plant at Longford is the onshore receiving point for oil and natural gas
output from production platforms in Bass Strait
. The Longford Gas Plant Complex consists of three gas processing
plants and one crude oil stabilisation plant. It was the primary provider of natural gas to Victoria, and provided some supply to New South Wales
.
(H
2O
) and hydrogen sulfide
(H
2S
). The water and H2S are removed before reaching the plant, leaving a hydrocarbon stream to be the feed to Gas Plant 1. This stream contained both gaseous and liquid components. The liquid component was known as "condensate
". The LPG
is further extracted by means of a shell and tube heat exchanger
, in which heated "lean oil" and cold "rich oil" (oil which has absorbed LPG) are pumped into the exchanger, cooling the lean oil and heating the rich oil.
A heat exchanger
is a vessel that allows the transfer of heat
from a hot stream to a cold stream, and so does not operate at a single temperature
, but experiences a range of temperatures throughout the vessel. Temperatures throughout GP905 normally ranged from 60 °C to 230 °C (140 °F to 446 °F). Investigators estimated that, due to the failure of the lean oil pump, parts of GP905 experienced temperatures as low as -48 °C. Ice had formed on the unit, and it was decided to resume pumping heated lean oil in to thaw it. When the lean oil pump resumed operation, it pumped oil into the heat exchanger at 230 °C (446 °F) - the temperature differential caused a brittle fracture in the exchanger (GP905) at 12.26pm.
About 10 metric tonnes of hydrocarbon vapour were immediately vented from the rupture. A vapour cloud formed and drifted downwind. When it reached a set of heaters 170 metres away, it ignited. This caused a deflagration
(a burning vapour cloud). The flame front burnt its way through the vapour cloud, without causing an explosion. When the flamefront reached the rupture in the heat exchanger, a fierce jet fire developed that lasted for two days.
The rupture of GP905 led to other releases and minor fires. The main fire was an intense jet fire emanating from GP905. There was no blast wave - the nearby control room was undamaged. Damage was localised to the immediate area around and above the GP905 exchanger.
Peter Wilson and John Lowery were killed in the accident and eight others were injured.
shut down the state's entire gas supply. The resulting gas supply shortage was devastating to Victoria's economy, crippling industry and the commercial sector (in particular, the hospitality industry which relied on natural gas for cooking). Loss to industry during the crisis was estimated at around A$1.3 billion
.
As natural gas was also widely used in houses in Victoria for cooking, water heating and home heating, many Victorians endured 20 days without gas hot-water or heating.
Gas supplies to Victoria resumed on 14 October. Many Victorians were outraged and upset to discover only minor compensation on their next gas bill, with the average compensation figure being only around $10.
was called into the explosion at Longford, headed by former High Court
judge Daryl Dawson
. The Commission sat for 53 days, commencing with a preliminary hearing on 12 November 1998 and concluding with a closing address by Counsel Assisting the Royal Commission on 15 April 1999.
Esso blamed the accident on worker negligence, in particular Jim Ward, one of the panel workers on duty on the day of the explosion.
The findings of the Royal Commission, however, cleared Ward of any negligence or wrong-doing. Instead, the Commission found Esso fully responsible for the accident:
Other findings of the Royal Commission included:
Certain managerial shortcomings were also identified:
by the Victorian WorkCover Authority. The jury found the company guilty of eleven breaches of the Occupational Health and Safety Act 1985, and Justice Philip Cummins imposed a record fine of $2 million in July 2001.
In addition, a class action was taken on behalf of businesses, industries and domestic users who were financially affected by the gas crisis. The class action went to trial in the Supreme Court on 4 September 2002, and was eventually settled in December 2004 when Esso was ordered to pay $32.5 million to businesses which suffered property damage as a result of the incident.
Following the Longford accident, Victoria introduced the Major Hazard Facilities Regulations to regulate safety at plants that contain major chemical hazards. These regulations impose a so-called "non-prescriptive" regime on facility operators, requiring them to "demonstrate" control of major chemical hazards via the use of a Safety Management System and a Safety Case.
Other states have also implemented similar regulatory regimes.
Esso
Esso is an international trade name for ExxonMobil and its related companies. Pronounced , it is derived from the initials of the pre-1911 Standard Oil, and as such became the focus of much litigation and regulatory restriction in the United States. In 1972, it was largely replaced in the U.S. by...
natural gas plant
Natural gas processing
Natural-gas processing is a complex industrial process designed to clean raw natural gas by separating impurities and various non-methane hydrocarbons and fluids to produce what is known as pipeline quality dry natural gas.-Background:...
at Longford
Longford, Victoria
Longford is a town in the Gippsland region of Victoria, Australia. At the 2006 census, Longford and the surrounding area had a population of 929.It was named after the town and county of Longford in Ireland....
in the Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n state of Victoria
Victoria (Australia)
Victoria is the second most populous state in Australia. Geographically the smallest mainland state, Victoria is bordered by New South Wales, South Australia, and Tasmania on Boundary Islet to the north, west and south respectively....
's Gippsland
Gippsland
Gippsland is a large rural region in Victoria, Australia. It begins immediately east of the suburbs of Melbourne and stretches to the New South Wales border, lying between the Great Dividing Range to the north and Bass Strait to the south...
region. On 25 September 1998, an explosion
Explosion
An explosion is a rapid increase in volume and release of energy in an extreme manner, usually with the generation of high temperatures and the release of gases. An explosion creates a shock wave. If the shock wave is a supersonic detonation, then the source of the blast is called a "high explosive"...
took place at the plant
Chemical plant
A chemical plant is an industrial process plant that manufactures chemicals, usually on a large scale. The general objective of a chemical plant is to create new material wealth via the chemical or biological transformation and or separation of materials. Chemical plants use special equipment,...
, killing two workers and injuring eight. Gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
supplies to the state of Victoria were severely affected for two weeks.
Context
In 1998, the Longford gas plant was owned by a joint partnership between EssoEsso
Esso is an international trade name for ExxonMobil and its related companies. Pronounced , it is derived from the initials of the pre-1911 Standard Oil, and as such became the focus of much litigation and regulatory restriction in the United States. In 1972, it was largely replaced in the U.S. by...
and BHP. Esso was responsible for the operation of the plant. Esso was a wholly owned subsidiary of US based company Exxon, which has since merged with Mobil, becoming ExxonMobil
ExxonMobil
Exxon Mobil Corporation or ExxonMobil, is an American multinational oil and gas corporation. It is a direct descendant of John D. Rockefeller's Standard Oil company, and was formed on November 30, 1999, by the merger of Exxon and Mobil. Its headquarters are in Irving, Texas...
. BHP has since merged with UK based Billiton becoming BHP Billiton
BHP Billiton
BHP Billiton is a global mining, oil and gas company headquartered in Melbourne, Australia and with a major management office in London, United Kingdom...
.
Built in 1969, the plant at Longford is the onshore receiving point for oil and natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...
output from production platforms in Bass Strait
Bass Strait
Bass Strait is a sea strait separating Tasmania from the south of the Australian mainland, specifically the state of Victoria.-Extent:The International Hydrographic Organization defines the limits of the Bass Strait as follows:...
. The Longford Gas Plant Complex consists of three gas processing
Natural gas processing
Natural-gas processing is a complex industrial process designed to clean raw natural gas by separating impurities and various non-methane hydrocarbons and fluids to produce what is known as pipeline quality dry natural gas.-Background:...
plants and one crude oil stabilisation plant. It was the primary provider of natural gas to Victoria, and provided some supply to New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
.
Normal processing procedure
The feed from the Bass Strait platforms consists of liquid and gaseous hydrocarbons, waterWater
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
(H
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
2O
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
) and hydrogen sulfide
Hydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...
(H
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
2S
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
). The water and H2S are removed before reaching the plant, leaving a hydrocarbon stream to be the feed to Gas Plant 1. This stream contained both gaseous and liquid components. The liquid component was known as "condensate
Natural gas condensate
Natural-gas condensate is a low-density mixture of hydrocarbon liquids that are present as gaseous components in the raw natural gas produced from many natural gas fields....
". The LPG
Liquified petroleum gas
Liquefied petroleum gas is a flammable mixture of hydrocarbon gases used as a fuel in heating appliances and vehicles. It is increasingly used as an aerosol propellant and a refrigerant, replacing chlorofluorocarbons in an effort to reduce damage to the ozone layer...
is further extracted by means of a shell and tube heat exchanger
Shell and tube heat exchanger
A shell and tube heat exchanger is a class of heat exchanger designs. It is the most common type of heat exchanger in oil refineries and other large chemical processes, and is suited for higher-pressure applications. As its name implies, this type of heat exchanger consists of a shell with a...
, in which heated "lean oil" and cold "rich oil" (oil which has absorbed LPG) are pumped into the exchanger, cooling the lean oil and heating the rich oil.
Explosion at Longford
During the morning of Friday 25 September 1998, a pump supplying heated lean oil to heat exchanger GP905 in Gas Plant No. 1 went offline for four hours, due to an increase in flow from the Marlin Gas Field which caused an overflow of condensate in the absorber.A heat exchanger
Heat exchanger
A heat exchanger is a piece of equipment built for efficient heat transfer from one medium to another. The media may be separated by a solid wall, so that they never mix, or they may be in direct contact...
is a vessel that allows the transfer of heat
Heat transfer
Heat transfer is a discipline of thermal engineering that concerns the exchange of thermal energy from one physical system to another. Heat transfer is classified into various mechanisms, such as heat conduction, convection, thermal radiation, and phase-change transfer...
from a hot stream to a cold stream, and so does not operate at a single temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
, but experiences a range of temperatures throughout the vessel. Temperatures throughout GP905 normally ranged from 60 °C to 230 °C (140 °F to 446 °F). Investigators estimated that, due to the failure of the lean oil pump, parts of GP905 experienced temperatures as low as -48 °C. Ice had formed on the unit, and it was decided to resume pumping heated lean oil in to thaw it. When the lean oil pump resumed operation, it pumped oil into the heat exchanger at 230 °C (446 °F) - the temperature differential caused a brittle fracture in the exchanger (GP905) at 12.26pm.
About 10 metric tonnes of hydrocarbon vapour were immediately vented from the rupture. A vapour cloud formed and drifted downwind. When it reached a set of heaters 170 metres away, it ignited. This caused a deflagration
Deflagration
Deflagration is a term describing subsonic combustion that usually propagates through thermal conductivity; hot burning material heats the next layer of cold material and ignites it. Most "fire" found in daily life, from flames to explosions, is deflagration...
(a burning vapour cloud). The flame front burnt its way through the vapour cloud, without causing an explosion. When the flamefront reached the rupture in the heat exchanger, a fierce jet fire developed that lasted for two days.
The rupture of GP905 led to other releases and minor fires. The main fire was an intense jet fire emanating from GP905. There was no blast wave - the nearby control room was undamaged. Damage was localised to the immediate area around and above the GP905 exchanger.
Peter Wilson and John Lowery were killed in the accident and eight others were injured.
Aftermath
The fire at the plant was not extinguished until two days later. The Longford plant was shut down immediately, and the state of Victoria was left without its primary gas supplier. Within days, the Victorian Energy Network CorporationVENCorp
VENCorp was responsible for the efficient operation of gas and electricity industries in Victoria, Australia. VENCorp, which was established in December 1997, was a Victorian State Government-owned entity within Victoria's privatised energy industries...
shut down the state's entire gas supply. The resulting gas supply shortage was devastating to Victoria's economy, crippling industry and the commercial sector (in particular, the hospitality industry which relied on natural gas for cooking). Loss to industry during the crisis was estimated at around A$1.3 billion
1000000000 (number)
1,000,000,000 is the natural number following 999,999,999 and preceding 1,000,000,001.In scientific notation, it is written as 109....
.
As natural gas was also widely used in houses in Victoria for cooking, water heating and home heating, many Victorians endured 20 days without gas hot-water or heating.
Gas supplies to Victoria resumed on 14 October. Many Victorians were outraged and upset to discover only minor compensation on their next gas bill, with the average compensation figure being only around $10.
Royal Commission
A Royal CommissionRoyal Commission
In Commonwealth realms and other monarchies a Royal Commission is a major ad-hoc formal public inquiry into a defined issue. They have been held in various countries such as the United Kingdom, Australia, Canada, New Zealand, and Saudi Arabia...
was called into the explosion at Longford, headed by former High Court
High Court of Australia
The High Court of Australia is the supreme court in the Australian court hierarchy and the final court of appeal in Australia. It has both original and appellate jurisdiction, has the power of judicial review over laws passed by the Parliament of Australia and the parliaments of the States, and...
judge Daryl Dawson
Daryl Dawson
Sir Daryl Michael Dawson, AC, KBE, CB Australian judge and naval officer, was a Justice of the High Court of Australia from 1982 to 1997.-Education:...
. The Commission sat for 53 days, commencing with a preliminary hearing on 12 November 1998 and concluding with a closing address by Counsel Assisting the Royal Commission on 15 April 1999.
Esso blamed the accident on worker negligence, in particular Jim Ward, one of the panel workers on duty on the day of the explosion.
The findings of the Royal Commission, however, cleared Ward of any negligence or wrong-doing. Instead, the Commission found Esso fully responsible for the accident:
- The causes of the accident on 25 September 1998 amounted to a failure to provide and maintain so far as practicable a working environment that was safe and without risks to health. This constituted a breach or breaches of Section 21 of the Occupational Health and Safety Act 1985.
Other findings of the Royal Commission included:
- the Longford plant was poorly designed, and made isolation of dangerous vapours and materials very difficult;
- inadequate training of personnel in normal operating procedures of a hazardous process;
- excessive alarm and warning systems had caused workers to become desensitised to possible hazardous occurrences;
- the relocation of plant engineers to MelbourneMelbourneMelbourne is the capital and most populous city in the state of Victoria, and the second most populous city in Australia. The Melbourne City Centre is the hub of the greater metropolitan area and the Census statistical division—of which "Melbourne" is the common name. As of June 2009, the greater...
had reduced the quality of supervision at the plant; - poor communication between shifts meant that the pump shutdown was not communicated to the following shift.
Certain managerial shortcomings were also identified:
- the company had neglected to commission a HAZOP (HAZard and OPerability) analysis of the heat exchange system, which would almost certainly have highlighted the risk of tank rupture caused by sudden temperature change;
- Esso's two-tiered reporting system (from operators to supervisors to management) meant that certain warning signs such as a previous similar incident (on 28 August) were not reported to the appropriate parties;
- the company's "safety culture" was more oriented towards preventing lost time due to accidents or injuries, rather than protection of workers and their health.
Legal ramifications
Esso was taken to the Supreme Court of VictoriaSupreme Court of Victoria
The Supreme Court of Victoria is the superior court for the State of Victoria, Australia. It was founded in 1852, and is a superior court of common law and equity, with unlimited jurisdiction within the state...
by the Victorian WorkCover Authority. The jury found the company guilty of eleven breaches of the Occupational Health and Safety Act 1985, and Justice Philip Cummins imposed a record fine of $2 million in July 2001.
In addition, a class action was taken on behalf of businesses, industries and domestic users who were financially affected by the gas crisis. The class action went to trial in the Supreme Court on 4 September 2002, and was eventually settled in December 2004 when Esso was ordered to pay $32.5 million to businesses which suffered property damage as a result of the incident.
Following the Longford accident, Victoria introduced the Major Hazard Facilities Regulations to regulate safety at plants that contain major chemical hazards. These regulations impose a so-called "non-prescriptive" regime on facility operators, requiring them to "demonstrate" control of major chemical hazards via the use of a Safety Management System and a Safety Case.
Other states have also implemented similar regulatory regimes.
External links
- Implications of the Esso Longford verdicts on the engineering profession Microsoft WordMicrosoft WordMicrosoft Word is a word processor designed by Microsoft. It was first released in 1983 under the name Multi-Tool Word for Xenix systems. Subsequent versions were later written for several other platforms including IBM PCs running DOS , the Apple Macintosh , the AT&T Unix PC , Atari ST , SCO UNIX,...
Document - Major Hazard Facilities - Worksafe
- Lessons for Seveso II from Longford, Australia Loss Prevention Bulletin Issue 158, 2001, IChemE, UK